BlackBerry service has been restored after a “critical severity outage” knocked out service to North American customers Monday afternoon, Research in Motion (RIM) said Monday night.

RIM statement:

“BlackBerry data services in the Americas experienced intermittent delays on late Monday afternoon (beginning approximately 3:30 pm eastern). Data service levels were restored in the early evening at approximately 6:30 pm eastern. Voice and SMS services operated normally during this time. No messages were lost and message queues began to be cleared after normal service levels were restored. RIM continues to focus on providing industry-leading reliability in its products and services and apologizes to customers for any inconvenience.”

UPDATE: RIM issued the following statement at 1pm EST Tuesday: We wanted to keep you informed about the BlackBerry data service interruption that occurred on Monday afternoon. RIM is continuing to investigate the exact cause and we will provide you with additional information as soon as we are able to verify the events that prompted the interruption. We appreciate your continued interest in BlackBerry and will keep you informed of any updates.